Smart congestion control for RRC connected mode in LTE systems

ABSTRACT

A UE establishes an RRC connection with a base station for an application in a mobile communication network. The UE acquires a barring indication that indicates whether scheduling request (SR) barring is applicable for the application. The UE then acquires prioritized barring parameters for SR barring if applicable. The prioritized barring parameters is associated with a priority of the application. Finally, the UE determines whether to send a scheduling request for an arrived packet based on the prioritized barring parameters. In one embodiment, the application is associated with a quality of service (QoS) class indicator (QCI), and the priority of the application is based on the QCI. The prioritized SR barring mechanism based on QCI can be applied for RRC Connected mode with finer granularity.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 from U.S.Provisional Application No. 61/948,814, entitled “The Method of SmartCongestion Controls”, filed on Mar. 6, 2014; the subject matter of whichis incorporated herein by reference.

TECHNICAL FIELD

The disclosed embodiments relate generally to LTE advanced systems, and,more particularly, to smart congestion control for both RRC Idle and RRCConnected UEs in LTE-Advanced systems.

BACKGROUND

FIG. 1 (Prior Art) illustrates a radio network congestion and a corenetwork congestion use case in an LTE network 100. LTE network 100comprises an application server 110, a packet data network gateway (PDNGW) 120, a serving GW 130, two base stations eNB141 and eNB142, and aplurality of user equipments (UEs). Radio network congestion occurs whenmassive concurrent data transmission takes place in the radio accessnetwork, as depicted by arrow 151. On the other hand, data congestionmay occur in the mobile core network or on the link between the mobilecore network and the application server 110 where the data trafficrelated to the application is aggregated, as depicted by arrow 152.

Modern networks use congestion control and congestion avoidancetechniques to try to avoid network congestion. LTE has specified severalbarring mechanisms for concurrent congestion control. Access ClassBarring (ACB) is a mechanism to limit the number of simultaneous accessattempts from certain UEs. All UEs are member of one out of ten randomlyallocated mobile populations, defined as access class 0 to 9. Thepopulation number is stored in UE's SIM/USIM. In addition, the UEs maybe members of one or more out of five special categories (e.g., AccessClass 11 to 15), also stored in the SIM/USIM. Under the ACB mechanism,the network operator may prevent certain UEs from making access attemptsor responding to pages in specific areas of a PLMN based on thecorresponding access class. Enhanced access barring (EAB) is an enhancedaccess barring mechanism to avoid Machine Type Communication (MTC)overload. Service Specific Access Control (SSAC) is used to applyindependent access control for telephony services such as IP MultimediaSubsystem multimedia telephony (MMTEL) services.

FIG. 2 (Prior Art) illustrates various barring mechanisms for congestioncontrol in an LTE system 200. LTE specifies several barring mechanismsfor concurrent congestion control in different layers. In non-accessstratum (NAS) layer, for RRC Idle mode, LTE specifies Service SpecificAccess Control (SSAC) for MMTEL services and EAB for MTC devices. ForRRC Connected mode, SSAC may be applied. In Access stratum (AS) layer,for RRC Idle mode, ACB is in general applicable to all types of servicesand devices. For RRC Connected mode, random access backoff, RRCreject/release, and scheduling request (SR) masking can be used as well.

Some of the barring mechanisms in LTE, however, have duplicate behaviorand therefore may cause quality degradation in some scenarios. Forexample, double barring of SSAC and ACB for MMTEL service de-prioritizesMMTEL service and LTE fails to prioritize MMTEL service over otherservices. Furthermore, congestion control for RRC Connected UEs becomesmore important as the trend is to keep UE in RRC Connected for dataapplications. However, LTE lacks congestion control mechanism for RRCConnected mode. Therefore, it is desirable to provide a feasiblecongestion control mechanism with a fine granularity that can prioritizeor deprioritize services based on operator's requirement. In addition,the congestion control mechanism can be applied for RRC Connected modeas well with proper granularity.

SUMMARY

A smart congestion control method is proposed for UEs in RRC Idle modeand in RRC Connected mode in a 3GPP LTE-Advanced network.

In one novel aspect, a UE initiates an MMTEL service in RRC Idle mode ina mobile communication network. The UE acquires access controlinformation from a base station. The access control informationindicates whether ACB is applicable to MMTEL service type. The UE thenperforms SSAC check for the MMTEL service based on the access controlinformation. The UE also performs ACB check for the MMTEL service if ACBis applicable to the MMTEL service. Otherwise, the UE bypasses the ACBcheck for the MMTEL service. The access control information comprisesSSAC configuration information, ACB parameters information, and ACBbypass information. In one embodiment, the MMTEL service type hasmultiple subtypes including voice, video, and text, and the ACB bypassinformation contains one or more indications, each indication indicateswhether ACB is applicable to an MMTEL service subtype. In anotherembodiment, the UE comprises a NAS layer and an AS layer, and the NASlayer forwards MMTEL service type indication to the AS layer fordetermining whether to bypass ACB. In yet another embodiment, afterSSAC/ACB check, the UE performs random access with prioritized RAbackoff. The RA backoff value is different for different service types,and the RA backoff value is contained in a new control element (CE) in arandom access response (RAR).

In another novel aspect, a UE establishes an RRC connection with a basestation for an application in a mobile communication network. The UEacquires a barring indication that indicates whether scheduling request(SR) barring is applicable for respective applications. The UE thenacquires prioritized barring parameters for SR barring if applicable.The prioritized barring parameters is associated with a priority of theapplication. Finally, the UE determines whether to send a schedulingrequest for an arrived packet based on the prioritized barringparameters. In one embodiment, the application is associated with aquality class indicator (QCI), and the priority of the application isbased on the QCI. In another embodiment, the UE comprises a NAS layerand an RRC layer, where the RRC layer forwards the barring indicationand the prioritized barring parameters to the NAS layer for determiningSR barring. In yet another embodiment, the prioritized barringparameters can be the same as or separate from the ACB barringparameters applied for RRC Idle mode, and the eNB signals a bitmap forindicating which prioritization should apply.

Other embodiments and advantages are described in the detaileddescription below. This summary does not purport to define theinvention. The invention is defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, where like numerals indicate like components,illustrate embodiments of the invention.

FIG. 1 (Prior Art) illustrates a radio network congestion use case and acore network congestion use case in an LTE network.

FIG. 2 (Prior Art) illustrates various barring mechanisms for congestioncontrol in an LTE system.

FIG. 3 illustrates a 3GPP LTE network that supports smart congestioncontrol mechanism in accordance with one novel aspect.

FIG. 4 is a simplified block diagram of a user equipment (UE) thatsupports certain embodiments of the present invention.

FIG. 5 illustrates a method of smart congestion control in RRC Idlemode.

FIG. 6 illustrates a method of smart congestion control in RRC Connectedmode.

FIG. 7 illustrates one embodiment of selective access control barring(ACB).

FIG. 8 illustrates another embodiment of selective access controlbarring (ACB).

FIG. 9 illustrates the barring rate performance of selective ACB.

FIG. 10 illustrates the delay performance of selective ACB.

FIG. 11 is a flow chart of a method of selective ACB for MMTEL servicefrom UE perspective in accordance with one novel aspect.

FIG. 12 is a flow chart of a method of selective ACB for MMTEL servicefrom eNB perspective in accordance with one novel aspect.

FIG. 13 illustrates one embodiment of smart congestion control in RRCConnected mode.

FIG. 14 is a flow chart of a method of smart congestion control in RRCConnected mode from UE perspective in accordance with one novel aspect.

FIG. 15 is a flow chart of a method of smart congestion control in RRCConnected mode from base station perspective in accordance with onenovel aspect.

DETAILED DESCRIPTION

Reference will now be made in detail to some embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings.

FIG. 3 illustrates a 3GPP LTE network 300 that supports smart congestioncontrol mechanism in accordance with one novel aspect. 3GPP LTE network300 comprises an application server 311 that provides various servicesby communicating with a plurality of user equipments (e.g., UE 314 asillustrated in FIG. 3). In FIG. 3, server 311 and a packet data networkgateway (PDN GW) 313 belong to part of a core network 310. UE 314 andits serving base station (eNB) 315 belong to part of a radio accessnetwork (RAN) 320. Server 311 communicates with UE 314 through PDN GW313, serving GW 316, and eNB 315. A mobility management entity (MME) 317communicates with eNB 315, serving GW 316 and PDN GW 313 for mobilitymanagement of wireless access devices in 3GPP network 300.

In the example of FIG. 3, server 311 provides variousservices/applications in application (APP) protocol layer. To providethe end-to-end services, server 311 communicates with the plurality ofUEs in the 3GPP network. Each UE (e.g. UE 314) comprises variousprotocol layer modules to support the end-to-end applications and dataconnections. In the application level, APP module 331 communicates withserver 311 in APP protocol layer (e.g., depicted by dashed line 341),which provides the end-to-end control/data. In the network or NAS level,NAS module 332 communicates with MME 317 in non-access stratum protocollayer (e.g., depicted by dashed line 342), which supports mobilitymanagement and other signaling functionality. In the radio networkaccess (RAN) or AS level, RRC module 333 communicates with eNB 315 inradio resource control (RRC) protocol layer (e.g., depicted by dashedline 343), which takes care of broadcast of system information, RRCconnection control, paging, radio configuration control, QoS control,etc.

LTE specifies several barring mechanisms for concurrent congestioncontrol in different layers. In AS layer, Access Class Barring (ACB) isa mechanism to limit the number of simultaneous access attempts fromcertain UEs. Under the ACB mechanism, the network operator may preventcertain UEs from making access attempts or responding to pages inspecific areas of a PLMN based on the corresponding access class. Thereare different ways to implementing access barring. For example, accessbarring is achieved via barring parameters including access probability(e.g., barring factor) and retry timer (e.g., barring time) performed atthe UE side. In NAS layer, Service Specific Access Control (SSAC) isused to apply independent access control for telephony services such asIP Multimedia Subsystem multimedia telephony (MMTEL) services. The SSACmechanism is similar to ACB, and access barring can be achieved viabarring parameters including access probability (e.g., barring factor)and retry timer (e.g., barring time) performed at the UE side. Thedouble barring of SSAC and ACB for MMTEL service de-prioritizes MMTELservice and LTE fails to prioritize MMTEL service over other services.

In one novel aspect, a smart congestion control mechanism is providedfor the network operator to control access attempts from UEs to preventoverload of the access network and/or the core network. In congestionsituations, the network operator can prioritize or de-prioritize certainservice types. For example, the network operator can de-prioritize MMTELservice during normal situation by applying double barring of SSAC/ACB.During special occasions when MMTEL service is expected to be morepopular, the network operator can prioritize MMTEL service by applyingACB bypassing. For example, in AS layer, eNB 315 determines SSACinformation, ACB information, and ACB bypass information based on accesscontrol configuration transmitted from MME 317 as depicted by line 351.The access control information is then broadcasted from eNB 315 to UE314 via system information block as depicted by line 352. Upon acquiringthe access control information, UE 314 attempts RRC access subject toSSAC/ACB control. If UE 314 gains RRC access, then UE 314 furtherattempts random access with backoff prioritization. Finally, after UE314 establishes RRC connection, eNB 315 determines whether to applyadditional barring control including SR masking in RRC Connected mode.

FIG. 4 is a simplified block diagram of a user equipment (UE) 401 thatsupports certain embodiments of the present invention. UE 401 comprisesmemory 411, a processor 412, a radio frequency (RF) module 413 coupledto antenna 414, a baseband module 415, a 3GPP protocol stack module 426supporting various protocol layers including NAS 425, AS/RRC 424,PDCP/RLC 423, MAC 422 and PHY 421, a TCP/IP protocol stack module 427,an application module APP 428, and a management module 430 including anaccess barring module 431, and an RRC connection management module 432.The access barring module may further comprise an SSAC module for NASlayer access control and an ACB module for AS layer access control. Thevarious function modules may be implemented and configured by software,firmware, hardware, and any combination thereof. The function modules,when executed by processor 412 (via program instructions contained inmemory 411), interwork with each other to allow UE 401 to performcertain embodiments of the present invention accordingly.

FIG. 5 illustrates a method of smart congestion control for a UE in RRCIdle mode. The UE comprises a NAS layer and an AS layer. When MMTELservice arrives from the NAS layer, the NAS layer performs SSAC check toverify if the UE is barred from NAS layer access. After satisfying theSSAC check, NAS layer notifies AS layer that a service is arrived and anRRC connection is required. Afterwards, the AS layer further performsACB check to verify if the UE is barred from AS layer access. On theother hand, for other mobile originated (MO) data service such as FTP,there is no NAS layer access control, and NAS layer could directlynotify AS layer that service request and only AS layer ACB check isperformed for MO data service. Therefore, the traditional double barringfor MMTEL service de-prioritizes MMTEL service. In accordance with onenovel aspect, the AS layer performs selective ACB. With selective ACB,the ACB check may be bypassed for MMTEL service if configured by thenetwork. This way, MMTEL service is not always de-prioritized. Instead,MMTEL service can be prioritized through bypassing ACB check in ASlayer. After the UE passes the AS layer access control, the UE starts acontention-based random access (RA) procedure with a backoff window togain access to the radio network. In accordance with another novelaspect, the RA backoff value is prioritized based on traffic type.Different backoff values are used for different traffic types. Aftercompleting the RA procedure, the UE establishes an RRC connection withthe network and enters RRC Connected mode.

FIG. 6 illustrates a method of smart congestion control in RRC Connectedmode. After the UE establishes an RRC connection for the application,the specific application is associated with a certain QoS classindicator (QCI) respectively. For example, there are total nine (9)QCIs, and each QCI is then mapped to a corresponding logical channelgroup (LCG). The MMTEL service may be associated with QCI1, while the MOdata service may be associated with QCI5 (the default QCI). Inaccordance with one novel aspect, additional barring control may beapplied for the subscribed applications, which have differentprioritizations (e.g., based on QCI). Different prioritization havedifferent barring parameters for the UE to decide whether schedulingrequest (SR) and buffer status report (BSR) can be sent. The networkwill grant transmission to the UE only if the UE is not barred fromsending SR/BSR.

For a UE to perform selective ACB, the network (eNB) needs to indicatethe bypass of ACB to the UE. In a first embodiment, the eNB uses a newinformation bit in SIB. The new information bit indicates whether ACBbypass should be applied for MMTEL service. In a second embodiment, theeNB changes the existing SSAC parameter, e.g., adding one bit toindicate whether ACB bypass should be applied for MMTEL service. In athird embodiment, a predefined ACB barring value is used to implicitlyindicate whether ACB bypass should be applied for MMTEL service. In afourth embodiment, separate new information bits in SIB are used forindividual MMTEL service subtypes including voice, video, and text. Forexample, three new information bits are defined in SIB, and each bitindicates whether ACB bypass should be applied for MMTEL voice, video,and text service respectively.

FIG. 7 illustrates one embodiment of selective access control barring(ACB) from UE perspective. In the example of FIG. 7, UE 701 comprises anapplication layer APP 702, a NAS layer NAS 703, and an AS layer AS 704.In step 711, APP 702 forwards an arrived MMTEL service to NAS 703. Instep 712, NAS 703 forwards the service request to AS 704. In step 713,AS 704 receives SIB2 broadcasted from eNB 705. SIB2 comprises variousaccess control information including SSAC configuration, ACB parameters,and ACB bypass information. In step 714, AS 704 forwards the receivedSSAC configuration and ACB bypass information to NAS 703. In step 715,NAS 703 performs SSAC check for the MMTEL service. If the UE passes theSSAC check, and if the ACB bypass information indicates to bypass ACBcheck for the corresponding MMTEL service type or subtype(s), then instep 716, NAS 703 request AS 704 to trigger the subsequence randomaccess (RA) procedure without ACB. In step 717, AS 704 sends a randomaccess preamble to eNB 705. In step 718, eNB 705 sends a random accessresponse (RAR) back to UE 701. In step 719, AS 704 forwards the RAR toNAS 703, which sends out an RRC request to AS 704 in step 720. Finally,in step 721, AS 704 sends the RRC request with establishment cause toeNB 705 for establishing an RRC connection.

FIG. 8 illustrates another embodiment of selective access controlbarring (ACB) from UE perspective. In the example of FIG. 8, UE 801comprises an application layer APP 802, a NAS layer NAS 803, and an ASlayer AS 804. In step 811, APP 802 forwards an arrived MMTEL service toNAS 803. In step 812, NAS 803 forwards the service request to AS 804. Instep 813, AS 804 receives SIB2 broadcasted from eNB 805. SIB2 comprisesvarious access control information including SSAC configuration, ACBparameters, and ACB bypass information. In step 814, AS 804 forwards thereceived SSAC configuration to NAS 803. In step 815, NAS 803 performsSSAC check for the MMTEL service. If the UE passes the SSAC check, thenin step 816, NAS 803 forwards the MMTEL service type and/or subtype(s)to AS 804. In step 817, AS 804 either performs ACB check or bypasses ACBcheck based on the indicated subtype(s), received ACB parameters and theACB bypass information. In this embodiment, NAS 803 informs AS 804 thearrived traffic type of MMTEL and/or the subtypes. As a result, AS 804triggers the subsequence random access (RA) procedure without ACB if thetraffic type satisfies the ACB bypass configuration. In step 818, AS 804sends a random access preamble to eNB 805. In step 819, eNB 705 sends arandom access response (RAR) back to UE 801. In step 820, AS 804forwards the RAR to NAS 803, which sends out an RRC request to AS 804 instep 821. Finally, in step 822, AS 804 sends the RRC request withestablishment cause to eNB 805 for establishing an RRC connection.

FIG. 9 illustrates the barring rate performance of selective ACB. Asillustrated in FIG. 9, for conventional MMTEL-voice service and MOservice, the barring rate (access prohibition probability) increases asthe ACB barring factor increases. However, for isolated MMTEL-voiceservice, if ACB bypass is applied, the barring rate decreases while theACB barring factor increases (assuming that the SSAC barring factor isfixed to 0.2). Therefore, it shows that under selective ACB, theMMTEL-voice service is prioritized over MO service by increasing the ACBbarring factor.

FIG. 10 illustrates the delay performance of selective ACB. Asillustrated in FIG. 10, for conventional MMTEL-voice service and MOservice, the delay performance (averaged access delay) increases as theACB barring factor increases. However, for isolated MMTEL-voice service,if ACB bypass is applied, the average access delay remains the samewhile the ACB barring factor increases (assuming that the SSAC barringfactor is fixed to 0.2). Therefore, it shows that under selective ACB,the MMTEL-voice service is prioritized over MO service by increasing theACB barring factor.

If access is not barred by the NAS/AS layer, then the UE starts acontention-based random access (RA) procedure with the network.Traditionally, MAC header will specify a backoff interval (BI) value forcontention resolution. A dedicated mapping table for BI value withrespect to backoff window size is applied for all traffic type. Inaccordance with another novel aspect, the RA backoff is prioritizedbased on traffic type. Different backoff values are applied fordifferent service or application type in order to provide morecongestion control granularity. In a first embodiment, different mappingtables are used for different traffic types. In a second embodiment, RAbackoff bypass is applied for certain traffic type. In a thirdembodiment, a new control element (CE) is used for carrying specificbackoff value in RAR. In a fourth embodiment, default backoff values areused for particular services. In one example, NAS layer notifies thetraffic type to AS layer for using corresponding backoff value. Inanother example, AS layer forward backoff parameters to NAS layer forselecting corresponding backoff value based on the traffic type.

FIG. 11 is a flow chart of a method of selective ACB for MMTEL servicefrom UE perspective in accordance with one novel aspect. In step 1101, aUE initiates an MMTEL service in a mobile communication network. In step1102, the UE acquires access control information from a base station.The access control information indicates whether ACB is applicable toMMTEL service type. In step 1103, the UE performs SSAC check for theMMTEL service based on the access control information. In step 1104, theUE performs ACB check for the MMTEL service if ACB is applicable to theMMTEL service. Otherwise, the UE bypasses the ACB check for the MMTELservice. The access control information comprises SSAC configurationinformation, ACB parameters information, and ACB bypass information. Inone embodiment, the MMTEL service type has multiple subtypes includingvoice, video, and text, and the ACB bypass information contains one ormore indications, each indication indicates whether ACB is applicable toan MMTEL service subtype. In another embodiment, the UE comprises a NASlayer and an AS layer, and the NAS layer forwards MMTEL service typeindication to the AS layer for determining whether to bypass ACB.

FIG. 12 is a flow chart of a method of selective ACB for MMTEL servicefrom eNB perspective in accordance with one novel aspect. In step 1201,a base station transmits access control information to a UE in a mobilecommunication network. The access control information indicates whetherACB is applicable to MMTEL service type. In step 1202, the base stationreceives a random access preamble from the UE. In step 1203, the basestation transmits a random access response (RAR) to the UE. The RARcomprises information on a random access (RA) backoff value. The accesscontrol information comprises SSAC configuration information, ACBparameters information, and ACB bypass information. In one embodiment,the MMTEL service type has multiple subtypes including voice, video, andtext, and the ACB bypass information contains one or more indications,each indication indicates whether ACB is applicable to an MMTEL servicesubtype. In another embodiment, the RA backoff value is different fordifferent service types, and the RA backoff value is contained in a newcontrol element (CE) in the RAR.

FIG. 13 illustrates one embodiment of smart congestion control in RRCConnected mode. In the example of FIG. 13, UE 1301 comprises a NAS layer1302 and an AS/RRC layer 1303. In step 1311, UE 1301 establishes an RRCconnection and radio bearer with its serving bases station eNB 1304 foran application. The application (and the radio bearer) is associatedwith a quality of service (QoS) class indicator (QCI) respectively, oris associated with an allocation and retention priority (ARP). In step1312, eNB 1304 transmits a prioritization indication to UE RRC 1303,which forwards the indication to UE NAS 1302 in step 1313. Theprioritization indication indicates whether barring control in RRCConnected mode should be applied or not. If no barring control in RRCConnected mode, then the base station will not transmit any barringcontrol parameters, and the UE is allowed to send scheduling requestwhenever needed. On the other hand, if barring control should be appliedin RRC Connected mode, then in step 1314, eNB 1304 broadcastsprioritized barring parameters to UE RRC 1303 via SIBx. UE RRC 1303 thenforwards the prioritized barring parameters to UE NAS 1302 in step 1315.

Different barring parameters are assigned to different prioritizationbased on the QCI/ARP of each application. For example, an applicationwith higher QCI is assigned to have lower barring factor and shorterbarring time, while an application with lower QCI is assigned to havehigher barring factor and longer barring time. Those barring parameterscan be separate and independent from the barring parameters of ACB inRRC Idle mode. Alternatively, the same barring parameters of ACB in RRCIdle mode can be used in RRC Connected mode, and the base station onlyneeds to signal the UE a bitmap indicating which prioritization shallapply. As mentioned earlier, there may have total 9 QCIs and differentapplications are associated with different QCIs. The bitmap would be a9-bit bitmap that each bit stands for a specific QCI. If the bit is “1”,it means the application associating with the corresponding QCI shallperform prioritized barring (using the same ACB parameter as in RRC Idlemode), otherwise, the application can initiate scheduling requestwithout prioritized barring. In addition, eNB 1304 can change thebarring parameters when modification period is coming. Suchprioritization barring based on QCI/ARP has finer granularity congestioncontrol for RRC Connected mode. Later on, in step 1316, a packet arrivesat UE NAS 1302. In step 1317, UE NAS 1302 applies prioritized barringfor the arrived packet. If the UE is not barred, then in step 1318, UENAS 1302 forwards a service request to UE RRC 1303. In step 1319, UE RRC1303 sends SR/BSR to eNB 1304. Finally, in step 1320, eNB 1304 sends anuplink grant to UE RRC 1303 for data transmission in response to theSR/BSR.

FIG. 14 is a flow chart of a method of smart congestion control in RRCConnected mode from UE perspective in accordance with one novel aspect.In step 1401, a UE establishes an RRC connection with a base station foran application in a mobile communication network. In step 1402, the UEacquires a barring indication that indicates whether scheduling request(SR) barring is applicable for the application. In step 1403, the UEacquires prioritized barring parameters for SR barring if applicable.The prioritized barring parameters is associated with a priority of theapplication. In step 1404, the UE determines whether to send ascheduling request for an arrived packet based on the prioritizedbarring parameters. In one embodiment, the application is associatedwith a quality class indicator (QCI), and the priority of theapplication is based on the QCI. In another embodiment, the UE comprisesa NAS layer and an AS/RRC layer, where the AS/RRC layer forwards thebarring indication and the prioritized barring parameters to the NASlayer for determining SR barring.

FIG. 15 is a flow chart of a method of smart congestion control in RRCConnected mode from base station perspective in accordance with onenovel aspect. In step 1501, a base station establishes an RRC connectionwith a UE for an application in a mobile communication network. In step1502, the base station transmits a barring indication that indicateswhether scheduling request (SR) barring is applicable for theapplication. In step 1503, the base station transmits prioritizedbarring parameters for SR barring if applicable. The prioritized barringparameters is associated with a priority of the application. In step1504, the base station receives a scheduling request for an arrivedpacket of the RRC connection from the UE based on the prioritizedparameters. In one embodiment, the application is associated with aquality class indicator (QCI), and the priority of the application isbased on the QCI. In another embodiment, the prioritized barringparameters can be separate from the ACB barring parameters for RRC Idlemode. In yet another embodiment, the prioritized barring parameters arethe same as the ACB parameters applied for RRC Idle mode, and the eNBsignals a bitmap for indicating which prioritization should apply for SRbarring.

Although the present invention has been described in connection withcertain specific embodiments for instructional purposes, the presentinvention is not limited thereto. Accordingly, various modifications,adaptations, and combinations of various features of the describedembodiments can be practiced without departing from the scope of theinvention as set forth in the claims.

What is claimed is:
 1. A method comprising: establishing a radioresource control (RRC) connection by a user equipment (UE) with a basestation for an application in a mobile communication network; acquiringa barring indication that indicates whether scheduling request (SR)barring of the established RRC connection is applicable for theapplication in RRC connected mode; acquiring prioritized barringparameters for SR barring associated with a priority of the applicationif SR barring is applicable, wherein the application is associated withan allocation and retention priority (ARP), and wherein the priority ofthe application is based on the ARP; and determining whether to send ascheduling request for an arrived packet of the established RRCconnection in RRC Connected mode based on the prioritized barringparameters.
 2. The method of claim 1, wherein the application isassociated with a quality class indicator (QCI), and wherein thepriority of the application is based on the QCI.
 3. The method of claim1, wherein the prioritized barring parameters comprises a prioritizedbarring factor and a prioritized barring time.
 4. The method of claim 1,wherein different applications with different priorities have differentbarring factors and barring times.
 5. The method of claim 1, wherein theUE comprises a NAS layer and an RRC layer, wherein the RRC layerforwards the barring indication and the prioritized barring parametersto the NAS layer for determining SR barring.
 6. The method of claim 1,wherein the UE also determines whether to send buffer status report(BSR) for the RRC connection based on the prioritized barringparameters.
 7. A user equipment (UE), comprising: a radio resourcecontrol (RRC) connection module that establishes an RRC connection witha base station for an application in a mobile communication network; areceiver that receives a barring indication that indicates whetherscheduling request (SR) barring of the established RRC connection isapplicable for the application in RRC connected mode, wherein thereceiver also receives prioritized barring parameters for SR barringassociated with a priority of the application if SR barring isapplicable, wherein the application is associated with an allocation andretention priority (ARP), and wherein the priority of the application isbased on the ARP; and a prioritized access barring module thatdetermines whether to send a scheduling request for an arrived packet ofthe established RRC connection in RRC Connected mode based on theprioritized barring parameters.
 8. The UE of claim 7, wherein theapplication is associated with a quality class indicator (QCI), andwherein the priority of the application is based on the QCI.
 9. The UEof claim 7, wherein the prioritized barring parameters comprises aprioritized barring factor and a prioritized barring time.
 10. The UE ofclaim 7, wherein different applications with different priorities havedifferent barring factors and barring times.
 11. The UE of claim 7,wherein the UE comprises a NAS layer and an RRC layer, wherein the RRClayer forwards the barring indication and the prioritized barringparameters to the NAS layer for determining SR barring.
 12. The UE ofclaim 7, wherein the UE also determines whether to send buffer statusreport (BSR) for the RRC connection based on the prioritized barringparameters.
 13. A method comprising: establishing a radio resourcecontrol (RRC) connection by a base station with a user equipment (UE)for an application in a mobile communication network; transmitting abarring indication that indicates whether scheduling request (SR)barring of the established RRC connection is applicable for theapplication; transmitting prioritized barring parameters for SR barringassociated with a priority of the application if SR barring isapplicable, wherein the application is associated with an allocation andretention priority (ARP), and wherein the priority of the application isbased on the ARP; and receiving a scheduling request for an arrivedpacket of the established RRC connection from the UE in RRC connectedmode based on the prioritized barring parameters.
 14. The method ofclaim 13, wherein the application is associated with a quality classindicator (QCI), and wherein the priority of the application is based onthe QCI.
 15. The method of claim 13, wherein the prioritized barringparameters comprises a prioritized barring factor and a prioritizedbarring time.
 16. The method of claim 15, wherein different applicationswith different priorities have different barring factors and barringtimes.
 17. The method of claim 13, wherein the base station broadcaststhe prioritized barring parameters via system information block (SIB).18. The method of claim 13, wherein the barring parameters areindependent from access control barring (ACB) parameters applied for RRCIdle mode.
 19. The method of claim 13, wherein the barring parametersare the same as access control barring (ACB) parameters applied for RRCIdle mode.